1. Field of the Invention
This invention relates generally electronic equipment, such as computers, and, more particularly, to apparatus and methods for cooling electronic devices using circulating fluids.
2. Background Information
Computer systems often require high reliability and high capacity of operation. Various approaches have been taken to providing such high-performance, high reliability systems. High density systems are typically rack mountable, with one or more processor modules occupying a prescribed space (e.g., a vertical slot) in the rack. A trend in recent times is to make the computers with smaller form factors. This means that more processors can be located in a rack. This has the advantage of increasing the processing density within the racks, and also the advantage of reducing the distance between the computer systems.
Components of computer systems may generate substantial amounts of heat during operation. Higher operating temperatures in electronic components are associated with decreased reliability of the components. To address this issue, some systems include fans or blowers to force air over the heat-generating components to cool the components.
Heat sinks may be attached to components to facilitate heat dissipation from the components. A heat sink is typically made of a thermally conductive material, such as aluminum, with a plurality of fins or pins on an exposed side of the heat sink. Heat is dissipated from the fins or pins to the surrounding air principally by thermal convection.
Some cooling systems use forced convection of fluids to carry heat from heat producing components such as microprocessors. One such system is a microchannel system. In a typical microchannel system, fluid is directed through a multitude of small channels in proximity with a heat producing component. A large number of microchannels may provide a large amount of surface area that facilitates cooling of the heat producing component. The fluid is carried away from the channels and through a pipe to a heat sink, where the heat can be rejected to the surroundings.
In a typical cooling system, a constant flow of fluid may be delivered at all times, to all impinging surfaces, of the heat producing component. In reality, however, the surface of the heat producing component will have significant temporal and spatial thermal variations. A cooling solution is desired that more effectively provisions cooling fluid when and where it is most needed.